1. Field of the Invention
The present invention generally relates to a diaphragm structure, and particularly relates to a diaphragm structure, of which on the thin-film metal coils are fixed by electrolytic bonding, thereby the thickness of a sounding apparatus monomer is greatly reduced.
2. The Prior Arts
According to the differences in structures and principles of sounding, sounding apparatus can be classified into several types such as moving coil type speakers, piezoelectric speakers, piezoelectric ceramic speakers and paper speakers. Amongst the above mentioned speakers, the most common one is the conventional moving coil type speaker. The structure of the moving coil type speaker is formed by the following steps: firstly, winding an enameled coil on the outer circumference of a cylindrical tube to form a voice coil; secondly, adhering one end of the voice coil at one side of a diaphragm; lastly, disposing the diaphragm at one side of a magnet to form a moving coil type speaker monomer. When using this type of monomer for sounding, corresponding audio frequency current is passed through the enameled coil such that the magnetic field of the coil is changed by electromagnetic induction to drive the diaphragm to vibrate, thereby vibrating the air to sound. The moving coil type monomer is advantageous in having good sound quality at low and medium frequency. However, due to its large size, moving coil type speakers are not suitable for apparatuses with small volumes. Besides, since the moving coil type speaker has a greater monomer thickness, it has poorer performance at high frequency.
In conventional monomer structures, voice coils are fixed onto the thin-film by ways of back adhesive. Since available adhesives in the art possess a certain thickness, such a fixing method would result in a monomer with a greater overall thickness; as a result, the overall size of a sounding apparatus, such as earphones, with such a monomer and the overall size of the earphones cannot be reduced. In addition, as the sensibility of the sounding apparatus is required to be improved, it is common to increase the magnetic flux density by increasing the number of coils. However, since the conventional fixation by back adhesive results in an overly thick thickness of the monomer after the number of the coils is increased, designs of the sounding apparatus and earphones are restricted.